Method and apparatus for bending a tubular member

ABSTRACT

An apparatus and method is disclosed for bending a tubular member into a zig-zag configuration, so that the tubular member is suitable for assembling into an open web joist. The method includes the steps of flattening one section of the tubular member, maintaining a grip on the flattened section and simultaneously bending the tubular member at either side of the flattened section. The apparatus provides a central flattening means adapted to flatten and grip a section of the tubular member, two outer flattening means each adapted to flatten and grip a section of the tubular member, the two outer flattening means being spaced equally apart from the central flattening means. Each of the flattening means are located on a separate movable carriage which are mounted on separate guide members. The carriages for the outer flattening means have their guide members in the same plane and in line and the carriage for the central flattening means has its guide members in the same plane and perpendicular to the guide members for the two outer flattening means carriages. Power means are provided for moving the central flattening means carriage along its guide members so that the central flattening means is out of line with the two outer flattening means.

United States Patent [191 Schwartz 51 Oct. 22, 1974 METHOD AND APPARATUS FOR BENDING A TUBULAR MEMBER [75] Inventor: Walter Schwartz, Winnipeg,

Manitoba, Canada [73] Assignee: Dominion Bridge Company Limited,

Montreal, Quebec, Canada [22] Filed: Mar. 14, 1973 [21] Appl. No.: 341,081

[30] Foreign Application Priority Data Dec. 5, 1972 Canada 158276 [52] U.S. Cl 72/383, 72/301, 72/DIG. 16 [51] Int. Cl B2ld 11/07 [58] Field of Search 72/383, 384, 385, 301, 72/308, 381, 382, DIG. 16; 29/155; 140/105 [56] References Cited UNITED STATES PATENTS 2,481,049 9/1949 Stamm et al 72/381 3,385,092 5/1968 Scott 72/381 3,628,369 12/1971 Williamson 72/385 Primary Examiner-Lowell A. Larson Attorney, Agent, or Firm-Fetherstonhaugh & Co.; Larson, Taylor & Hinds [57] ABSTRACT .An apparatus and method is disclosed for bending a tubular member into a zig-zag configuration, so that the tubular member is suitable for assembling into an open web joist. The method includes the steps of flattening one section of the tubular member, maintaining a grip on the flattened section and simultaneously bending the tubular member at either side of the flattened section. The apparatus provides a central flattening means adapted to flatten and grip a section of the tubular member, two outer flattening means each adapted to flatten and grip a section of thetubular member, the two outer flattening means being spaced equally apart from the central flattening means. Each of the flattening means are located on a separate movable carriage which are mounted on separate guide members. The carriages for the outer flattening means have their guide members in the same plane and in line and the carriage for the central flattening means has its guide members in the same plane and perpendicular to the guide members for the two outer flattening means carriages. Power means are provided for moving the central flattening means carriage along its guide members so that the central flattening means is out of line with the two outer flattening means.

9 Claims, 4 Drawing Figures .51 54 2 4A 10 28 27 2o 21 47M ,46 4 37 3C 1 I: f- I I I 2 19 '45 I "it a 17 l 18 2G I I I41 7 13 1e 50 55 as 54 Z2 4 l 50 5! Ii 14 I 3O 32 15 31 a 23 2 53 51 as PAIENIED 0121221974 SEUZIF4 METHOD AND APPARATUS FOR BENDING A TUBULAR MEMBER This invention relates to a bending apparatus and more particularly to a machine for bending a tubular member into at least one V-shaped configuration.

In the past open web joists have been made from rods which are first bent into a zig-zag configuration before being welded to top and bottom chords. In larger spans, where a higher strength to weight ratio isrequired, the zig-zag rod is replaced with short straight sections of a structural angle or a tubular member. These sections require more time for fitting and assembly as each section end must be joined preferably by welding to the chords.

Devices presently used for bending tubular members,

generally do so in one operation, and do not provide a flattened section suitable for resistance welding.

It is an object of the present invention to provide an apparatus and a process for forming a tubular member into a V-shaped configuration with the tip of the V being flattened suitable for welding to another structural member.

A further objectis to provide an apparatus for flattening a plurality of sections of a tubular member and bending the tubular member into a zig-zag configuration.

With these and other objects in view there is provided a method of bending a tubular member into at 7 least one V-shaped configuration comprising the steps of flattening at least one section of the tubular member, maintaining a pressure grip on the flattened section and simultaneously bending the tubular member at either side of the flattened section.

Furthermore there is provided an apparatus for forming a tubular member into a zig-zag configuration comprising a central flattening means adapted to flatten and grip a section of the tubular member, two outer flattening means each adapted to flatten and grip a section of the tubular member, the three flattening means being in the same plane and in line, the two outer flattening means spaced equally apart from the central flattening means, each flattening means located on a separate movable carriage mounted on separate guide members, the two carriages for the outer flattening means having their guide members in the same plane and in line, the carriage for the central flattening means having its guide members in the same plane and perpendicular to the guide members for the two outer flattening means carriages and located between the two, and power means for moving the central flattening means carriage along its guide members so that the central flattening means is out of line with the two outer flattening means.

In drawings which illustrate embodiments of the invention,

FIGS. 1, 2 and 3 represent top plan views showing the sequence of operation of the apparatus according to the present invention.

FIG. 4 shows an enlarged detail of a flattened section of tube under pressure with bends at either side of the flattened section.

Referring now to FIGS. 1, 2 and 3, a left hand guide member 10 and a right hand guide member 11 each comprising two rails or guides parallel to each other. The left hand guide member 10 and right hand guide member 11 are in line and in the same horizontal plane.

In between the left hand guide member and the right hand guide member 11 is a central guide member 12. The central guide member 12 is perpendicular to the left hand guide member 10 and right hand guide member 11, but in the same horizontal plane as these two members. The central guide member 12, like the other two members, has two rails or guides parallel to each other. On the left hand guide member 10 is slideably located a movable carriage or slide 13 preferably formed from a steel plate 14 and having mounted thereon a hydraulic cylinder 15. A movable piston arm 16 from the hydraulic cylinder is connected to a crushing jaw 17 which slides between two guides 18 to flatten and hold a section of a tubular member 19 against a back plate 20, which is supported by a support gusset 21 attached to the steel plate 14. The hydraulic cylinder 15 is connected to the steel plate 14 by bolts 22 and has a support plate 23 immediately behind the cylinder 15 with two support gussets 24 behind the support plate 23 attached to the steel plate 14.

The movable carriage 13 slides on the left hand guide member 10 and is connected to an air cylinder 25 positioned in the centre of the left hand guide member 10 adjacent the central guide member 12. The air cylinder 25 has a connection 26 to the frame of the bending device at the central guide member 12 and has a piston arm 27 connected to a bracket 28 on the underside of the steel plate 14 of the movable carriage 13.

The right hand guide member 11 has a movable carriage 29 with a hydraulic cylinder 30 attached by bolts 31 to a steel plate 32. A movable piston arm 33 from the hydraulic cylinder 30 is connected to a crushing jaw 34 which slides between two guides 35 to flatten and hold a section of the tubular member 19 against a back plate 36 which is supported by a support gusset 37 attached to the steel plate 32. A support plate 38 positioned behind the hydraulic cylinder 30 has two support gussets 39 attached to the steel plate 32. An air cylinder 40 similar to air cylinder 25 is positioned in the centre of the right hand guide member 11 adjacent the central guide member 12, and has a connection 41 to the frame of the bending device at the central guide member 12. A piston arm 42 from the air cylinder 40 is connected to a bracket43 on the underside of the steel plate 32.

A central movable carriage 44 which slides on the central guide member 12, moves perpendicular to the movable carriage 13 on the left hand guide member 10 and the movable carriage 29 on the right hand guide member 11. A hydraulic cylinder 45 is attached by bolts 46 to a steel plate 47. The hydraulic cylinder 45 has a movable piston arm 48 connected to a crushing jaw 49 which slides between two guides 50 to flatten and hold a section of the tubular member 19 against a back plate 51 which is supported by a support gusset 52 attached to the steel plate 47. A support plate 53 positioned behind the hydraulic cylinder 45 has two support gussets 54 attached to the steel plate 47.

The central guide member 12 extends backwards to form an extended frame 55 with a support plate 56 to support a hydraulic cylinder 57. The cylinder 57 rests between the two rails of the central guide member 12 at the same end as the hydraulic cylinder 45 on the central movable carriage 44. A piston arm 58 from the hydraulic cylinder 57 is connected to a bracket 59 on the underside of the steel plate 47 of the central movable carriage 44.

H6. 1 shows the bending apparatus in the initial position. The tubular member 19 is shown with one side resting against the back plate 20 of the left hand movable carriage 13 and the back plate 36 of the right hand movable carriage 29. At the same time, the back plate 51 of the central movable carriage 44 touches the other side of the tubular member 19. The movement of the central movable carriage 44 along the central guide member 12 can be set as required in order to put the desired depth of bend into the tubular member 19.

FIG. 4 shows a crushing jaw 60 resting against a flattened section 61 of a tubular member 62. It is seen that in the flattened section both sides of the tube meet thus enabling resistance welding to be performed through the flattened section of the tube. The flattened section 16 is resting up against a back plate 63. The central movable carriage has been moved in this particular figure, thus a left hand bend 64 and a right hand bend 65 appear on either side of the flattened section 61. The crushing jaw 60 has a radius 66 at the bottom end thereof such that the tubular member radius 67 is kept within desired limits and is not too great to cause stress or fatigue at that point. The preferred tubular member radius 67 is not less than one-eighth of an inch.

Before commencing operation, the apparatus is first adjusted for the particular diameter of tube to be bent and the desired depth of the V required in the tubular member. If the thickness or gauge of the tube varies, it is not necessary to reset the bending apparatus, as the vertical distance or depth of the zig-zag configuration remains the same being set by the distance from the two outer back plates 20 and 36 to the central back plate 51. The central movable carriage 44 is located in such a position so that the distance from the left and right hand back plates 20 and 36 to the central back plate 51 is slightly larger than the diameter of the tubular member 19. Thus, a tubular member 19 is easily placed between the back plates and the crushing jaws of the apparatus. The movement of the central movable carriage 44 along the central guide member 12 is controlled by a stop so that when the hydraulic cylinder 57 pushes this central movable carriage 44 it will only slide as far as the stop thus giving the desired depth of V in the tubular member. FIG. 1 shows a half formed V-shape in the tubular member 19 formed in a previous operation, and this is located at the right hand side of the apparatus so that it lines up between the right hand crushing jaw 34 and back plate 36. When the tubular member 19 has been lined up in the machine, the hydraulic cylinders 15, 30 and 45 are first activated, and these in turn push the crushing jaws 17, 34 and 49 up against the tubular member 19. The crushing jaws 17, 34 and 49 each flatten a section of the tubular member so that the two sides of the tubular member are touching. The pressure from the hydraulic cylinders 15, 30 and 45 is maintained on the three crushing jaws 17, 34 and 49 to grip the three flattened sections, and the hydraulic cylinder 57 mounted in the extended frame 55 of the central guide member 12 is next activated to push the central movable carriage 44 along the central guide member l2. As the piston arm 58 from the hydraulic cylinder 57 slowly moves the central movable carriage 44, the tubular member 19 commences to bend at the points at the end of each flattened section adjacent to each of the crushing jaws. The section of tubular member 19 held by the central crushing jaw 49 bends on each side in the configuration shown in H0. 4. As the central movable carriage 44 slides along the central guide member 12, both the left hand movable carriage l3 and the right hand movable carriage 29 slide on their guide members in towards the centre of the apparatus. As the carriages 13 and 29 move in towards the centre, the piston arms 27 and 42 move into the air cylinders 25 and 40. This movement is preferably assisted by stored air in an accumulator (not shown). The air assist is regulated so that it does not provide quite enough power to move the carriages l3 and 29 on their own, but gives an assist as the central movable carriage 44 starts to move commencing the bend in the tubular member. The bending speed is controlled by the flow of hydraulic fluid into the cylinder 57 which moves the central movable carriage 44 along the central guide member 12. When the central movable carriage 44 reaches the preset stop, the bend configuration is complete. Once the bend configuration has been completed, the hydraulic pressure is released from the hydraulic cylinders 15, 30 and 45, and the crushing jaws 17, 34 and 49 open. The tubular member 19 may then belifted and removed from the apparatus. The movable carriages 13, 29 and 44 are then returned to their initial position. The carriages l3 and 29 are returned by compressed air being passed into the low pressure side of 'the air cylinders 25 and 40. This forces the air in the opposite side of the cylinder into the accumulator (not shown) which is then held by an electric solenoid valve (not shown) for the next bend operation. The tubular member 19 is moved along and placed such that the section flattened by the crushing jaw 17 on the left hand movable carriage 13 is positioned under the crushing jaw 34 of the right hand movable carriage 29. The sequence then commences over again to form another V-shaped configuration. This sequence of operation continues until a zig-zag configuration has been made which is suitable for forming a web of an open web joist. Alternatively, only one V-shaped configuration is required suitable for welding, by regular electrode or resistance type to a structural member to form a strong connection suitable for many types of open structural frames.

The three hydraulic cylinders 15, 30 and 45 operating the crushing jaws 17, 34 and 49 are preferably connected to a hydraulic power source by means of flexible tubing (not shown). The motions of the crushing jaws are preferably controlled by a push button which operates an electric solenoid valve controlling the hydraulic fluid flow to the cylinders from a hydraulic power source such as a portable hydraulic power pack. It is not essential to have an electrically powered hydraulic source, a manual hydraulic jack has been found to operate adequately. The power to the hydraulic cylinder 57 in the extended frame 55 of the central guide member 12 is preferably from a hydraulic power source, preferably a portable hydraulic power pack and the motions of the central movable carriage 44 is preferably controlled by push button which operates electric solenoid valves controlling the air flow to the two air cylinders 25 and 40 and hydraulic fluid flow to the individual cylinder 57. This system may also be operated manually with merely a connection to a compressed air supply.

Whereas one embodiment of the present invention has been fully described, it will be apparent to those skilled in the art that a number'of changes may be made to this embodiment without detracting from the spirit or scope of the present invention. For instance, where hydraulic cylinders and air cylinders are shown with the operating means of the present embodiment, it will be apparent to those skilled in the art that mechanical bending means may also be used. Furthermore, the air cylinders 25 and 40 for moving the left hand movable carriage 13 and right hand movable carriage 29 may be replaced with hydraulic cylinders.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A method of bending a tubular member into a zigzag configuration comprising the steps of flattening three sections of the tubular member at two outside locations and one central location with two outside flattening and gripping means and one central flattening and gripping means, respectively, thereby forming two outside flattened sections, said central means being movable in a perpendicular direction to a line through the two outside flattened sections and each said outside means being freely movable in the direction of said line; maintaining a pressure grip on each of the flattened sections with saidoutside means and said central means; moving said central means perpendicular to said line for a predetermined distance; simultaneously with the moving of the central means, allowing said outside means to be pulled towards each other along said line by said tubular member and controllably assisting the moving of said outside means, and hence the movement of said outside flattened sections, with fluid actuated means by controlling the flow of fluid to said fluid actuated means such that said assistance alone is unable to move the two outside flattened sections, thus forming a v-shaped configuration in the tubular member; releasing the pressure grip from the flattened sections; moving the tubular member to a new location wherein one of the outside flattened sections just formed is positioned in the place of the other outside section just formed and repeating the above steps.

2. A method as claimed in claim 1 wherein said tubular member is flattened by compressing said tube with a jaw means having a radius of curvature at the outer ends thereof, said flattening being such that both sides of said tube are forced into contact with each other and a corresponding radius of curvature is formed on the inner surface of said tubular member in contact with said jaw means at each end of said flattened sections.

3. An apparatus for forming a substantially straight tubular member into a zig zag configuration compris- 1ng:

a central guide member; two outer guide members located in the same plane in line with each other, said central guide member being disposed between said two outer guide members in the same plane therewith and perpendicular thereto;

a movable central carriage and two movable outer carriages respectively mounted for independent movement on said central guide member and said two outer guide members;

a central flattening means mounted on said central carriage for flattening and gripping a section of the tubular member;

two outer flattening means mounted on said two outer carriages, respectively, for flattening and gripping repective sections of the tubular member;

and fluid operated power means for moving said central carriage and said central flattening means a predetermined distance along said central guide member, whereby upon the movement of said central carriage said outer carriages and the corresponding said outer flattening means when in a gripping relationship with the tubular members are pulled towards said central guide member by the tubular member; and fluid operated return means connected to said outer carriages for returning said outer carriages to a starting position after operation, said outer carriages moving independently of each other and of said central carriage.

4. Apparatus as claimed in claim 3 and further including fluid operated assisting means for controllably assisting and dampening the movement of said outer carriages, said assisting means being controllable by controlling the flow of operating fluid thereto.

5. Apparatus as claimed in claim 4 wherein said assisting means is also said power means.

6. Apparatus as claimed in claim 4 wherein said assisting means includes an air cylinder mounted at the adjacent ends of each of the guide members for said two outer carriages, said air cylinder having a piston arm connected to said outer carriage, a compressed air supply for the air cylinder, and a bleed control valve for controlling the air bleeding from said valve air cylinder and thereby controlling the dampening of said piston arm in said air cylinder.

7. Apparatus as claimed in claim 3 wherein each said flattening means includes a flattening jaw, a back plate, cooperating with said jaw for flattening a section of the tubular member, and fluid operated means for moving said jaw, all said jaws and back plates being in the same plane.

8. Apparatus as claimed in claim 7 wherein said flattening jaw has a radius of curvature at the outer ends thereof such that upon the flattening of said tubular member, a corresponding radius of curvature is formed on the inner surface of the tubular member in contact with said jaw means at each end of said flattened sections.

9. Apparatus as claimed in claim 6 wherein said guide members are disposed in a horizontal plane and said flattening means and said carriages are movable in a horizontal plane. 

1. A method of bending a tubular member into a zig-zag configuration comprising the steps of flattening three sections of the tubular member at two outside locations and one central location with two outside flattening and gripping means and one central flattening and gripping means, respectively, thereby forming two outside flattened sections, said central means being movable in a perpendicular direction to a line through the two outside flattened sections and each said outside means being freely movable in the direction of said line; maintaining a pressure grip on each of the flattened sections with said outside means and said central means; moving said central means perpendicular to said line for a predetermined distance; simultaneously with the moving of the central means, allowing said outside means to be pulled towards each other along said line by said tubular member and controllably assisting the moving of said outside means, and hence the movement of said outside flattened sections, with fluid actuated means by controlling the flow of fluid to said fluid actuated means such that said assistance alone is unable to move the two outside flattened sections, thus forming a v-shaped configuration in the tubular member; releasing the pressure grip from the flattened sections; moving the tubular member to a new location wherein one of the outside flattened sections just formed is positioned in the place of the other outside section just formed and repeating the above steps.
 2. A method as claimed in claim 1 wherein said tubular member is flattened by compressing said tube with a jaw means having a radius of curvature at the outer ends thereof, said flattening being such that both sides of said tube are forced into contact with each other and a corresponding radius of curvature is formed on the inner surface of said tubular member in contact with said jaw means at each end of said flattened sections.
 3. An apparatus for forming a substantially straight tubular member into a zig-zag configuration comprising: a central guide member; two outer guide members located in the same plane in line with each other, said central guide member being disposed between said two outer guide members in the same plane therewith and perpendicular thereto; a movable central carriage and two movable outer carriages respectively mounted for independent movement on said central guide member and said two outer guide members; a central flattening means mounted on said central carriage for flattening and gripping a section of the tubular member; two outer flattening means mounted on said two outer carriages, respectively, for flattening and gripping repective sections of the tubular member; and fluid operated power means for moving said central carriage and said central flattening means a predetermined distance along said central guide member, whereby upon the movement of said central carriage said outer carriages and the corresponding said outer flattening means when in a gripping relationship with the tubular members are pulled towards said central guide member by the tubular member; and fluid operated return means connected to said outer carriages for returning said outer carriages to a starting position after operation, said outer carriages moving independently of each other and of said central carriage.
 4. Apparatus as claimed in claim 3 and further including fluid operated assisting means for controllably assisting and dampening the movement of said outer carriages, said assisting means being controllable by controlling the flow of operating fluid thereto.
 5. Apparatus as claimed in claim 4 wherein said assisting means is also said power means.
 6. Apparatus as claimed in claim 4 wherein said assisting means includes an air cylinder mounted at the adjacent ends of each of the guide meMbers for said two outer carriages, said air cylinder having a piston arm connected to said outer carriage, a compressed air supply for the air cylinder, and a bleed control valve for controlling the air bleeding from said valve air cylinder and thereby controlling the dampening of said piston arm in said air cylinder.
 7. Apparatus as claimed in claim 3 wherein each said flattening means includes a flattening jaw, a back plate, cooperating with said jaw for flattening a section of the tubular member, and fluid operated means for moving said jaw, all said jaws and back plates being in the same plane.
 8. Apparatus as claimed in claim 7 wherein said flattening jaw has a radius of curvature at the outer ends thereof such that upon the flattening of said tubular member, a corresponding radius of curvature is formed on the inner surface of the tubular member in contact with said jaw means at each end of said flattened sections.
 9. Apparatus as claimed in claim 6 wherein said guide members are disposed in a horizontal plane and said flattening means and said carriages are movable in a horizontal plane. 